Currently, spring type music boxes are very common and applications are wide spread. However, existing music boxes have the following disadvantages:
1. A music box can breakdown easily as the fragile parts are prone to damage during transportation and installation. In particular, a slight push at the speed regulator can dislocate its axis of rotation, which will cause the speed regulator to rotate unproperly and may even stall the rotation.
2. When the music box is in motion, the rhythm is irregular due to the variations in the spring tension, and the music becomes unpleasant.
3. In most of the music boxes, the gears in the transmission systems are usually made of metal. To avoid rusting, the gears are electroplated or coated with anti-rust paint. This can achieve the anti-rust effect temporarily, but gears still rust after long period of use and movements of the music box will become unsmooth.